Apparatus and method for transmitting and receiving TBS information in an HSDPA communication system

ABSTRACT

An HSDPA (High Speed Downlink Packet Access) communication system is disclosed. A Node B reduces a size of a field transmitting TBS (Transport Block Set) information for user data based on an MCS (Modulation and Coding Scheme) level assigned to the user data and the number of codes assigned to the user data, before transmission, instead of transmitting an intact size of the actually transmitted transport block for the user data, among TFRI (Transport Format Resource Information) transmitted to a UE (User Equipment) over a shared control channel.

PRIORITY

[0001] This application claims priority to an application entitled“Apparatus and Method for Transmitting and Receiving TBS Information inan HSDPA Communication System” filed in the Korean Industrial PropertyOffice on Oct. 5, 2001 and assigned Serial No. 2001-61543, the contentsof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to an HSDPA (High SpeedDownlink Packet Access) communication system, and in particular, to anapparatus and method for transmitting TBS (Transport Block Set) sizeinformation for user data.

[0004] 2. Description of the Related Art

[0005] In general, HSDPA refers to a scheme for transmitting data usingHS-DSCH (High Speed-Downlink Shared Channel), a downlink data channelfor supporting high-speed downlink packet transmission, and itsassociated control channels in a UMTS (Universal MobileTelecommunication System) communication system. AMC (Adaptive Modulationand Coding), HARQ (Hybrid Automatic Retransmission Request), and FCS(Fast Cell Selection) schemes have been proposed in order to support theHSDPA. The AMC, HARQ and FCS schemes will be described herein below.

[0006] First, a description of the AMC will be made. The AMC is a datatransmission scheme for adaptively determining a modulation scheme and acoding scheme of a data channel according to a channel condition betweena specific Node B and a UE (User Equipment), thus to increase theoverall utilization efficiency of the Node B. Therefore, the AMCsupports a plurality of modulation schemes and coding schemes, andmodulates and codes a data channel signal by combining the modulationschemes and the coding schemes. Commonly, each combination of themodulation schemes and the coding schemes is called “MCS (Modulation andCoding Scheme),” and there are defined a plurality of MCS levels of #1to #n according to the number of the MCSs. That is, the AMC adaptivelydetermines an MCS level according to a channel condition of a UE and aNode B to which the UE is wirelessly connected, thereby increasing theentire utilization efficiency of the Node B.

[0007] Next, a description will be made of the FCS. The FCS is a schemefor fast selecting a cell having the best channel condition among aplurality of cells, when a UE supporting the HSDPA (hereinafter referredto as “HSDPA UE”) is located in a cell overlapping region, or a softhandover region. Specifically, in the FCS, if an HSDPA UE enters a celloverlapping region between a first Node B and a second Node B, the HSDPAUE establishes radio links to a plurality of cells, i.e., the first NodeB and the second Node B. Here, a set of the cells to which the HSDPA UEhas established the radio links is called an “active set.” The UEreduces overall interference by receiving HSDPA packet data only fromthe cell maintaining the best channel condition among the cells includedin the active set. Here, a cell in the active set, which transmits HSDPApacket data due to its best channel condition, is called a “best cell,”and the HSDPA UE periodically checks channel conditions of the cells inthe active set and transmits a best cell indicator to the cellsbelonging to the active set in order to replace the current best cellwith a new best cell having the better channel condition. The best cellindicator includes a cell ID of a cell selected as a best cell, and thecells in the active set receive the best cell indicator and detect thecell ID included in the best cell indicator. Each of the cells in theactive set determines whether the received best cell indicator includesits own cell ID. As a result of the determination, if the best cellindicator includes its own cell ID, the corresponding cell transmitspacket data to the HSDPA UE over HS_DSCH.

[0008] Finally, a description will be made of the HARQ, especiallyn-channel SAW HARQ (Stop and Wait Hybrid Automatic RetransmissionRequest). The HARQ newly proposes the following two plans in order toincrease transmission efficiency of the existing ARQ (AutomaticRetransmission Request). First, a retransmission request and a responseare exchanged between a UE and a Node B. Second, defective data istemporarily stored, and combined with retransmitted data of thecorresponding data. Further, the HSDPA has introduced the n-channel SAWHARQ in order to make up for a shortcoming of the conventional SAW ARQ.The SAW ARQ does not transmit the next packet data until it receives ACKfor the previous packet data. Therefore, in some cases, the SAW ARQ mustawait ACK, although it can currently transmit the next packet data.However, in the n-channel SAW HARQ, the next packet data is continuouslytransmitted before ACK for the previous packet data is received, therebyincreasing utilization efficiency of channels. That is, if n logicalchannels are established between a UE and a Node B, and the n logicalchannels can be identified by time and unique channel numbers, then theUE can recognize a channel over which packet data was received, andrearrange the received packets in the right reception order, orsoft-combine the received packets.

[0009] In a communication system supporting the HSDPA (hereinafter,referred to as HSDPA communication system) which increases communicationefficiency by supporting AMC, FCS and HARQ, a plurality of UEs sharesome of downlink transmission resources. The downlink transmissionresources include transmission power and OVSF (Orthogonal VariableSpreading Factor) codes (or orthogonal codes). The HSDPA communicationsystem uses 10 OVSF codes for SF (Spreading Factor=16, and 20 OVSF codesfor SF=32.

[0010] In the HSDPA communication system, a plurality of UEs cansimultaneously use a plurality of available OVSF codes at a specifictime. That is, in the HSDPA communication system, it is possible toenable OVSF code multiplexing among a plurality of UEs at a specifictime. The OVSF code multiplexing will be described with reference toFIG. 1.

[0011]FIG. 1 illustrates an exemplary method of assigning OVSF codes ina general HSDPA communication system. A description of FIG. 1 will bemade for SF=16.

[0012] Referring to FIG. 1, OVSF codes are defines as C(i,j) accordingto the positions of a code tree. In an OVSF code C(i,j), ‘i’ denotes theSF value and ‘j’ denotes the order of the corresponding OVSF code fromthe leftmost side in the OVSF code tree. For example, C(16,0) indicatesan OVSF code with SF=16 located in the first place from the leftmostside in the OVSF code tree. In FIG. 1, for example, 10 OVSF codes of a7^(th) OVSF code C(16,6) to a 16^(th) OVSF code C(16,15) are assigned tothe HSDPA communication system. The 10 OVSF codes can be multiplexed toa plurality of UEs, as illustrated in Table 1. TABLE 1 Time User t0 t1t2 A C(16,6)˜C(16,7) C(16,6)˜C(16,8)  C(16,6)˜C(16,10) B C(16,8)˜C(16,10)  C(16,9)˜C(16,10) C(16,11)˜C(16,14) CC(16,11)˜C(16,15) C(16,11)˜C(16,15) C(16,15)

[0013] In Table 1, A, B and C denote users (or UEs), which are using theHSDPA communication system. As illustrated in Table 1, the users A, Band C perform code multiplexing on the OVSF codes assigned to the HSDPAcommunication system at timing points t0, t1 and t2. The number of OVSFcodes to be assigned to the UEs and their positions on the OVSF codetree are determined by the Node B, and the Node B determines the numberof OVSF codes and their positions taking into consideration an amount ofuser data for each UE stored in the Node B.

[0014] The HSDPA communication system proposes that such controlinformation as the OVSF code information should be transmitted to UEsover downlink control channels. For better understanding, reference willbe made to a channel structure for the HSDPA communication system.

[0015] The HSDPA communication system includes high-speed downlinkshared channels (HS-DSCH), downlink control channels and uplink controlchannels. The high-speed downlink shared channel transmits user data toUEs using OVSF codes assigned to the HSDPA communication system. Inorder to support the AMC, HARQ and FCS schemes newly introduced tosupport the HSDPA communication system, it is necessary to exchangecontrol information between the Node B and the UE, and the controlinformation is transmitted over the downlink control channel and theuplink control channel. The control information transmitted over theuplink control channel includes (i) channel quality information (CQI)periodically reported to the Node B by the UE, (ii) an ACK(Acknowledgement) signal used by the UE to report whether received userdata is defective, and (iii) best cell information used by the UE toreport a cell providing the best channel condition by comparing channelconditions of the cells within its coverage.

[0016] In addition, control information transmitted over the downlinkcontrol channel includes (i) HI (HS-DSCH Indicator) indicating to a UEthat user data will be transmitted over a high-speed downlink sharedchannel, (ii) MCS level information, (iii) TBS (Transport Block Set)size information, (iv) OVSF code information to be assigned to thecorresponding UE, (v) HARQ information, and (vi) CRC (Cyclic RedundancyCheck) information. Of the control information transmitted over thedownlink control channel, the sum of the MCS level information, the TBSsize information and the OVSF code information is called “TFRI(Transport Format Resource Information).”

[0017] The control information stated above is transmitted over twocontrol channels of an associated DPCH (dedicated physical channel) anda SCCH (shared control channel). The “associated dedicated physicalchannel” means a dedicated physical channel established between a UE anda Node B, both supporting the HSDPA communication, on a one-to-onebasis, and the dedicated physical channel transmits the HI. The HIindicates whether HSDPA service data will be transmitted to a UE over ahigh-speed downlink shared channel in the near future. If the HSDPAservice data is transmitted to the UE, the HI indicates a shared controlchannel over which the UE should receive the concerned controlinformation, among a plurality of shared control channels used in theHSDPA communication system. For example, in the case where 4 sharedcontrol channels exist in the HSDPA communication system, if the 4shared control channels are assigned unique integers 0 to 3 and the HIis comprised of 2 bits, then (1) non-transmission of the HI means thatthere exists no HSDPA service data to be transmitted to thecorresponding UE, (2) HI=0(00) indicates that control information forthe HSDPA service data should be received over a shared control channel#0, (3) HI=1(01) indicates that control information for the HSDPAservice data should be received over a shared control channel #1, (4)HI=2(10) indicates that control information for the HSDPA service datashould be received over a shared control channel #2, and (5) HI=3(11)indicates that control information for the HSDPA service data should bereceived over a shared control channel #3,

[0018] The shared control channel transmits the remaining controlinformation except the HI, and a structure of the shared control channelwill be described with reference to FIG. 2.

[0019]FIG. 2 illustrates a structure of a shared control channel in acommon HSDPA communication system. Referring to FIG. 2, the sharedcontrol channel has a 2 ms period comprised of 3 slots. The reason thatthe shared control channel transmits a signal at a period of 2 ms isbecause a data transmission unit over the high-speed downlink sharedchannel is 3 slots. For example, the ongoing standardization sessionproposes that one of the 3 slots which become the data transmission unitof the high-speed downlink shared channel transmits the HARQinformation, and the remaining 2 slots transmit the TFRI and the CRC,respectively. If the UE detects an HI field filled with informationwhile continuously monitoring the HI field on an associated dedicatedphysical channel established between the UE and the Node B, the UE readsinformation on a corresponding shared control channel designated by theHI information and receives a high-speed downlink shared channelcorresponding to the information read from the corresponding sharedcontrol channel.

[0020] In the HSDPA communication system, information needed to properlyprocess data received by a physical layer of the UE includes TB(Transport Block) size information, TBS size information, channel codinginformation, modulation information, rate matching information, and codeinformation. On the information stated above, the channel codinginformation and the modulation information are transmitted from the NodeB to the UE through MCS level information, while the code information istransmitted from the Node B to the UE through OVSF code information. Inaddition, a size of the transport block is determined during initialcall setup, and the size of the transport block remains unchanged (i.e.,fixed size) while the call is maintained, so it is not necessary toseparately transmit information on the size of the transport block fromthe Node B to the UE.

[0021] Further, the TBS size information indicates the number oftransport blocks transmitted for a single TTI (Transmission TimeInterval), and the rate matching information indicates a repetition orpuncturing technique performed on user data by a physical layer of theNode B performs repetition or puncturing. The TBS size information istransmitted over the TFRI field illustrated in FIG. 2, and the ratematching information is not transmitted separately, because the ratematching technique is determined depending on the TBS size.

[0022] Next, a structure of a physical layer for a transmitter in theHSDPA communication system will be described with reference to FIG. 3.

[0023]FIG. 3 illustrates a channel structure of a physical layer for atransmitter in a common HSDPA communication system. Referring to FIG. 3,transport blocks to be transmitted are transmitted from an upper layerto a physical layer, i.e., over a transport channel. The transportblocks transmitted from the upper layer undergo concatenation orsegmentation according to their size. For example, in FIG. 3, thetransport blocks transmitted from the upper layer undergo concatenation(Step 301). Here, the transport blocks are transmitted from the upperlayer to the physical layer for each TTI. The transport blockstransmitted in the TTI unit constitute a transport block set, and thenumber of transport blocks transmitted over the transport block setbecomes a size of the transport block set. Header information isattached to the transport blocks, or the transport block set transmittedfrom the upper layer (Header Attachment) (Step 302). The headerinformation may include such information as serial numbers that can beused for sequentially arranging the transport blocks in the transportblock set at a receiver corresponding to the transmitter. CRC isattached to the header information-attached transport block set (Step303). Here, for the CRC, a 24-bit CRC operation can be considered.

[0024] The CRC-attached transport block set is segmented into codeblocks with a size proper for channel coding for error correcting codes(Step 304), and then subject to channel coding for channel transmission(Step 305). Here, the channel-coded data is called a “coded block.”After the code block segmentation, i.e., at a point D4, information bitsconstituting the transport blocks are converted into a symbol at a pointD5 through the channel coding. The coded block undergoes rate matchingtaking into consideration a length of a physical layer frame and aspreading factor in order to actually transmit the coded block to thephysical layer (Step 306). That is, the rate matching is a process ofmatching a size of the coded block to an amount of information that canbe actually transmitted over the physical channel. For example, if thenumber of symbols output through the channel coding is D5 and the numberof symbols finally transmitted over the physical channel is D9, then thenumber of symbols after the rate matching is matched to D9. That is, forthe rate matching, puncturing is performed for D5>D9 and repetition isperformed for D9>D5, thus to match the number of symbols at a point D5to the number of symbols at a point D9.

[0025] The rate-matched data is segmented in a unit that can betransmitted over a physical channel (Physical Channel Segmentation)(Step 307). The physical channel segmentation is performed to segmentthe whole data in a size proper for each code, since a high-speeddownlink shared channel can be comprised of a plurality of codes. Thephysical channel-segmented data is interleaved in order to prevent aburst error (Step 308), and the interleaved data is finally mapped to aphysical channel and then transmitted over the physical channel(Physical Channel Mapping) (Step 309).

[0026] An amount of user data to be transmitted is changed as follows,as the user data passes through the processes illustrated in FIG. 3.

[0027] D1=TB_Size (size of transport block)*TBS₁₃ Size (size oftransport lock set)

[0028] D2=D1+Header_Size (size of header)

[0029] D3=D2+CRC (e.g., 24 bits)

[0030] D4=D3

[0031] D5=D4*1/CR (where CR denotes a coding rate)

[0032] D6=D5+RM (size of rate matching)

[0033] D7=D6

[0034] D8=D7

[0035] D9=D8={(TB_Size*TBS_Size+Header_Size+CRC)/CR+RM}

[0036] Further, in FIG. 3, a transmission unit of the user data ischanged as follows, as the user data passes through the processesillustrated in FIG. 3. The transmission unit becomes an IB (informationbit) unit at D1 to D4, a symbol unit at D5 to D8, and a MS (modulatedsymbol) unit at D9. That is, the information bits are converted to asymbol through channel coding, and the symbol is converted to amodulated symbol through modulation.

[0037] Since the D9 means the total sum of data actually transmittedover the physical channel, it can be expressed as

D9=NC*Code_capa=NC*[((chip rate per time slot)/SF)*(number of time slotsper TTI)*MO)]=NC*MO*480 (3 time slots)*2560 (chip rate per timeslot)/16(SF)  Equation (1)

[0038] In Equation (1), NC denotes the number of codes, Code_capadenotes an amount of data that can be transmitted by one code, SFdenotes a spreading factor, and MO denotes a modulation order. Further,in Equation (1), a unit of the data amount becomes a symbol unit,Equation (1) can be rewritten as Equation (2). Here, it is assumed thatSF=16.

[TB_Size*TBS+Header_Size+CRC]/CR+RM=NC*480*MO  Equation (2)

[0039] Further, Equation (2) can be written as

RM=NC*480*MO−[TB_Size*TBS_Header_Size−CRC]/CR  Equation (3)

[0040] In Equation (3), if repetition is performed for rate matching,the parameter RM becomes a positive number, and if puncturing isperformed for rate matching, the parameter RM becomes a negative value.

[0041] A data amount in each process of FIG. 3 will be described withreference to FIG. 4.

[0042]FIG. 4 illustrates an amount of data in each process in thechannel structure of the physical layer of FIG. 3. Before a descriptionof FIG. 4, it should be noted that an amount of data finally transmittedover a physical channel is D9 as described in conjunction with FIG. 3,and the D9 is defined by a Node B at a certain timing point. That is,the D9 is determined based on the number of codes assigned to a given UEat a certain timing point and an MCS level. The transport block sizeTB_Size, the CRC size and the header size Header_Size are also constantswhich are not changed while the corresponding call is maintained.However, the transport block set size TBS_Size is a variable which ischanged according to an amount of data for the UE, stored in the Node B.In other words, in Equations (1) to (3), parameters which are changedfor each TTI include TBS (Transport Block Set), NC (Number of Codes), MO(Modulation Order), and CR (Coding Rate). These parameters aretransmitted from the Node B to the UE for each TTI over a TFRI field onthe shared control channel.

[0043] Referring to FIG. 4, when transport blocks are transmitted froman upper layer, the transport blocks undergo transport blockconcatenation according to their sizes as illustrated in conjunctionwith FIG. 3, and an amount of the concatenated transport blocks becomesD1. When header and CRC are attached to the concatenated transportblocks, an amount of the header/CRC-attached transport blocks becomesD3. When the header/CRC-attached information bits undergo code blocksegmentation and channel coding, an amount of the channel-coded databecomes D5. When D5 symbols are rate matched, an amount of therate-matched data becomes D6. When D6 symbols are subject to physicalchannel segmentation, an amount of the segmented data becomes D7. Here,D6 is equal to D7 in a data amount, but rate-matched symbols aresegmented according to an amount of the physical channel. In FIG. 4, itis assumed that repetition is performed for the rate matching.

[0044] A rate matching process by the physical layer structure of FIG. 3will be described with reference to FIGS. 5A and 5B.

[0045]FIGS. 5A and 5B illustrate a common rate matching technique.Referring to FIGS. 5A and 5B, if a Node B, or a transmitter determines arate matching technique, then the physical layer channel structure ofFIG. 3 repeats or punctures coded blocks represented by D5 at regularintervals according to the rate matching technique, and transmits therate-matched coded blocks to a UE, or a receiver after channelprocessing. The receiver then inserts 0's in the punctured portion (0Insertion) if the rate matching value (or parameter) is a negativevalue, i.e., if the coded blocks underwent puncturing, in order to matcha size of the coded blocks to D5, and then provides the 0-inserted codedblocks to a channel decoder.

[0046] In contrast, if the rate matching value is a positive number,i.e., if the coded blocks underwent repetition, the receiver sums up therepeated bits in order to match a size of the coded blocks to D5, andprovides the rate-matched coded blocks to the channel decoder. That is,the receiver secures correct channel decoding, when it recognizes a ratematching value transmitted by the transmitter. Further, in the HSDPAcommunication system, information on the transport block set (TBS), thenumber of codes (NC) and the coding rate (CR) is reported from a Node Bto a UE for each TTI, thus to enable the Node B and the UE to calculatethe same rate matching value. Although the UE can correctly determinethe number (or TBS size) of transport blocks transmitted from the Node Bby calculating the rate matching value, the Node B transmits to the UEthe TBS size information for each TTI, i.e., transmits the downlinkcontrol information unnecessarily, causing an unnecessary waste ofdownlink channel resources.

SUMMARY OF THE INVENTION

[0047] It is, therefore, an object of the present invention to providean apparatus and method for transmitting and receiving TBS sizeinformation for user data in an HSDPA communication system.

[0048] It is another object of the present invention to provide anapparatus and method for reducing a size of control informationtransmitted over a shared control channel in an HSDPA communicationsystem.

[0049] It is further another object of the present invention to providean apparatus and method for detecting a TBS size using a rate matchingvalue in an HSDPA communication system.

[0050] To achieve the above and other objects, the present inventionprovides a method for transmitting TBS (Transport Block Set) informationto a UE (User Equipment) in a high-speed packet communication system.The method comprises the steps of determining at least one Modulationorder among a plurality of modulation orders and at least one code amonga plurality of codes, determining the number of radio frame data bitsbased on the determined modulation order and the number of thedetermined codes, comparing the number of coded bits for a user datawith the number of radio frame data bits, setting a flag indicating arepetition if the number of coded bits for a user data is less than thenumber of radio frame data bits, setting a flag indicating a puncturingif the number of coded bits for a user data is greater than the numberof radio frame data bits; and transmitting the TBS information includingthe flag.

[0051] To achieve the above and other objects, the present inventionprovides a method for transmitting TBS (Transport Block Set) informationto a UE (User Equipment). The method comprises the steps of determiningat least one modulation order among a plurality of modulation orders andat least one code among a plurality of codes, determining a first numberof information bits that can be transmitted with the determinedmodulation order and the number of the determined codes, determining asecond number of information bits that can be transmitted with thedetermined modulation order and the number of the determined codes minusone and determining a third number of transport blocks that can betransmitted with the first number of information bits, determining afourth number of transport blocks that can be transmitted with thesecond number of information bits, and then transmitting a differencebetween the third number of transport blocks and the fourth number oftransport blocks.

[0052] To achieve the above and other objects, the present inventionprovides a method for receiving TBS (Transport Block Set) information ina high-speed packet communication system in which a Node B separatestransmission information bits into a plurality of transport blocks eachhaving a first number of bits, transmits a TBS including a stream of thetransport blocks and transmits information on the TBS to a UE (UserEquipment) without transmitting TBS size information indicating thenumber of the transport blocks. The method comprises the steps ofreceiving over a downlink shared channel an modulation order assigned tothe TBS, the number of codes assigned to the TBS, and arepetition/puncturing flag indicating whether the TBS underwentrepetition or puncturing, determining a second number of informationbits that can be transmitted with the assigned modulation order and thenumber of the assigned codes, calculating a third number of transportblocks by rounding up a valued determined by dividing the second numberof information bits by the first number of bits, and calculating afourth number of transport blocks by rounding down a value determined bydividing the second number of information bits by the first number ofbits, if the received repetition/puncturing flag indicates that the TBSunderwent repetition, determining the size of the TBS as the thirdnumber of transport blocks, and determining a rate matching value bysubtracting a product of the third number of transport blocks and thefirst number of bits from the second number of information bits, and ifthe received repetition/puncturing flag indicates that the TBS underwentpuncturing, determining the size of the TBS as the fourth number oftransport blocks, and determining a rate matching value by subtracting aproduct of the fourth number of transport blocks and the first number ofbits from the second number of information bits.

[0053] To achieve the above and other objects, the present inventionprovides an apparatus for transmitting TBS (Transport Block Set)information to a UE (User Equipment) without transmitting TBS sizeinformation indicating the number of transport blocks in a high-speedpacket communication system which separates transmission informationbits into a plurality of transport blocks each having a given number ofbits and transmits a TBS including a stream of the transport blocks. Theapparatus comprising comprises an MCS (Modulation and Coding Scheme)level controller for assigning one MCS level among a plurality of MCSlevels according to channel quality information received from the UE, acode assigner for assigning at least one code among a plurality of codesaccording to the number of the transmission information bits, a ratematching controller for determining the number of transmittableinformation bits based on the determined MCS level and the number of thedetermined codes, and a transmitter for transmitting the assigned MCSlevel, the number of the assigned codes, and the repetition flag or thepuncturing flag, over a downlink, wherein if the number of coded bitsfor the transmission information bits is less than the number oftransmittable information bits, repeating some of the coded bits atregular intervals and assigning a repetition flag indicting therepetition, and if the number of coded bits is greater than or equal tothe number of transmittable information bits, puncturing some of thecoded bits at regular intervals and assigning a puncturing flagindicting the puncturing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The above and other objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

[0055]FIG. 1 illustrates an exemplary method of assigning OVSF codes ina general HSDPA communication system;

[0056]FIG. 2 illustrates a structure of a shared control channel in acommon HSDPA communication system;

[0057]FIG. 3 illustrates a channel structure of a physical layer for atransmitter in a common HSDPA communication system;

[0058]FIG. 4 illustrates a size of data in each process in the channelstructure of the physical layer of FIG. 3;

[0059]FIGS. 5A and 5B illustrate a common rate matching technique;

[0060]FIG. 6 illustrates a channel structure of a physical layer for atransmitter in an HSDPA communication system according to a firstembodiment of the present invention;

[0061]FIG. 7 is a flow chart illustrating an operating process of atransmitter according to a first embodiment of the present invention;

[0062]FIG. 8 is a flow chart illustrating an operating process of atransmitter according to a second embodiment of the present invention;

[0063]FIG. 9 illustrates a TBS variation TBS_variation(X,Y) available ina state where X codes are assigned and an MCS level Y is assigned,according to a third embodiment of the present invention;

[0064]FIG. 10 is a block diagram illustrating a structure of atransmitter for an HSDPA communication system according to an embodimentof the present invention;

[0065]FIG. 11 is a block diagram illustrating a structure of a receiverfor an HSDPA communication system according to an embodiment of thepresent invention;

[0066]FIGS. 12A to 12D schematically illustrate an operation of the ratematching controller of FIG. 10; and

[0067]FIGS. 13A to 13D schematically illustrate an operation of the ratematching controller of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0068] A preferred embodiment of the present invention will be describedherein below with reference to the accompanying drawings. In thefollowing description, well-known functions or constructions are notdescribed in detail since they would obscure the invention inunnecessary detail.

[0069] Before a description of the present invention, the followingshould be noted. In an HSDPA (High Speed Downlink Packet Access)communication system, a Node B determines scheduling, code assignmentand MCS (Modulation and Coding Scheme) level for user data to betransmitted to a UE (User Equipment). The scheduling is closed relatedto the number of transport blocks (TBs) to be transmitted to a UE at acertain timing point, while the code assignment and the MCS level areclosely related to an amount of data to be transmitted to the UE at thecorresponding timing point. This will be described with reference toFIG. 3. The scheduling is related to an amount of data, or informationbits of transport blocks transmitted from D1, or an upper layer, and thenumber of assigned codes and the assigned MCS level are related to anamount, D9, of data actually transmitted over a physical channel. Thatis, the Node B determines the MCS level and the code assignment takinginto consideration a channel condition at a corresponding timing pointand an amount of data to be transmitted to other UEs, i.e., determinesan amount, D9, of data to be transmitted to the corresponding UE.Further, the Node B determines the number, D1, of transport blocks inaccordance with the determined data amount D9. Therefore, a size oftransport block set (TBS), i.e., the number of transport blockstransmitted becomes a dependent variable which depends upon a capacityof the physical channel at the corresponding timing point.

[0070] As described in conjunction with FIG. 3, the capacity, D9, of thephysical channel is defined as

D9=NC*480*MO  Equation (4)

[0071] In Equation (4), NC denotes the number of codes, and MO denotes amodulation order. Equation (4) is calculated in a symbol unit.

[0072] Further, the capacity of the physical channel can be expressed interms of information bits, as follows.

P_CAPA=NC*480*MO*CR  Equation (5)

[0073] In Equation (5), P_CAPA denotes the capacity of the physicalchannel expressed in terms of information bits. The MO and CR (CodingRate) are determined based on the MCS level, and the NC is determinedbased on the entire traffic size at a corresponding timing point. As aresult, P_CAPA becomes a time-varying function which is changed from themaximum capacity to the minimum capacity. However, from the viewpoint ofthe Node B, the P_CAPA at a certain timing point means a quantity oftransmission resources that can be used by the Node B at thecorresponding timing point, so it is necessary to match as manytransport blocks as possible to the P_CAPA in order to efficiently usethe transmission resources. Therefore, a transport block set (TBS),i.e., the number of transport blocks transmitted for one TTI (TransportTime Interval) is matched to the P_CAPA as shown in Equation (6).

TBS_estimated=(P_CAPA−CRC(Cyclic Redundancy Check)−Header_(—Size)/)TB_Size

TBS _(—)1=RU(TBS_estimated)

TBS _(—)2=RD(TBS_estimated)  Equation (6)

[0074] In Equation (6), RU denotes rounding up and RD denotes roundingdown.

[0075] The Node B selects TBS_(—)1 or TBS_(—)2 as a transport block set(TBS) for the corresponding timing point.

[0076] In addition, the P_CAPA is a time-varying function, and theirmaximum value P_CAPA_MAX and minimum value P_CAPA_MIN are defined as

P_CAPA_MIN=NC_MIN*480*MO_MIN*CR_MIN

P_CAPA_MAX=NC_MAX*480*MO_MAX*i CR_MAX  Equation (7)

[0077] In Equation (7), NC_MIN denotes the minimum number of codes thatcan be assigned by the Node B, and NC_MAX denotes the maximum number ofcodes that can be assigned by the Node B. Further, MO_MIN denotes theminimum modulation order applicable to the Node B, and MO_MAX denotesthe maximum modulation order applicable to the Node B. In addition,CR_MIN denotes the minimum coding rate applicable to the Node B, andCR_MAX denotes the maximum coding rate applicable to the Node B. Sincethe product of MO and CR is matched to the MCS level on a one-to-onebasis, Equation (7) can be rewritten as

P_CAPA_MIN=NC_MIN*480*MCS _(—)1

P_CAPA_MAX=NC_MAX*480*MCS_MAX  Equation (8)

[0078] In Equation (8), MCS_(—)1 denotes the product of MO and CR for anMCS level 1, and MCS_MAX denotes the product of MO and CR for themaximum MCS level. Therefore, the minimum number, TBS_MIN, of transportblocks that can be transmitted for one TTI becomes 1, and the maximumnumber, TBS_MAX, of transport blocks that can be transmitted for one TTIcan be derived from P_CAPA_MAX of Equation (8). That is, TBS_MAXestimate=(P_CAPA_MAX−CRC−Header_Size)/TB_Size, so the maximum size of atransport block set to be actually transmitted becomesTBS_MAX=RU(TBS_MAX_estimated).

[0079] Therefore, the conventional SCCH (Shared Control Channel)structure for the HSDPA communication system includes information on theTBS_MIN and the TBS_MAX. That is, a TBS field indicating sizeinformation of a transport block set with a size RU[log2(TBS_MAX−1] mustbe included in TFRI (Transport Format Resource Information), thus usinga large quantity of the shared control channel resource.

[0080] Accordingly, the present invention proposes a method for reducinga size of the TBS information transmitting the TBS size information inthe TFRI field in order to reduce an amount of data transmitted over theshared control channel, thereby increasing utilization efficiency of thedownlink shared channel resource.

[0081] The method for reducing a size of the TBS field will be describedwith reference to three different embodiments.

[0082] (1) First Embodiment

[0083] The first embodiment of the present invention reduces a size ofthe TBS field based on the fact that a size of the TBS field is alwaysmatched to the P_CAPA on a one-to-one basis except for a special case.

[0084] As stated above, a Node B determines the TBS size, or an amountof the user data to be transmitted to a given UE at a certain timingpoint, and at the same time, determines an MCS level and code assignmentat the corresponding timing point. That is, at a certain timing point,the Node B first determines P_CAPA and then determines its associatedTBS in accordance with Equation (6). As illustrated in Equation (6), TBSmatched to a certain P_CAPA includes TBS_(—)1 and TBS_(—)2. The TBS_(—)1corresponds to a case where puncturing is performed for rate matching,and the TBS_(—)2 corresponds to a case where repetition is performed forrate matching. The Node B calculates TBS_(—)1 and TBS_(—)2 for thecorresponding P_CAPA using Equation (6), and then selects the calculatedTBS_(—)1 or TBS_(—)2 as TBS for the corresponding timing point. Afterdetermining the TBS, the Node B performs rate matching in accordancewith the determined TBS, and then informs the UE whether a rate matchingtype for the TBS is puncturing or repetition. Then, the UE can calculateTBS from the P_CAPA and determine a rate matching value RM based on thecalculated TBS. In conclusion, since the Node B is simply required toinform the UE whether the rate matching type is puncturing or repetitionusing flag, instead of personally transmitting the TBS value, the UE isallowed to assign only one bit to the TBS field in the TFRI field. Forexample, if the rate matching type performed on the TBS is puncturing,the UE sets the TBS field to ‘0’ before transmission, and if ratematching type performed on the TBS is repetition, the UE sets the TBSfield to ‘1’ before transmission.

[0085] In the first embodiment of the present invention, a TBS size tobe transmitted to a corresponding UE at a certain timing point is validwhen it is larger than or equal to TBS_(—)2 at the corresponding timingpoint. However, when the TBS size TBS_actual to be actually transmittedto the corresponding UE at the certain timing point is less thanTBS_(—)2, the transport blocks are repeated up to TBS_(—)2 to match theTBS_(—)2 to the TBS_actual. Further, since the transport block ismatched to RLC-PDU (Radio Link Control-Protocol Data Unit) on aone-to-one basis and the RLC-PDU is assigned a serial number forrepetition check, the repetition performed in a transport block unitdoes not affect the system operation.

[0086] Now, a channel structure of a physical layer for a transmitter inan HSDPA communication system according to a first embodiment of thepresent invention will be described with reference to FIG. 6.

[0087]FIG. 6 illustrates a channel structure of a physical layer for atransmitter in an HSDPA communication system according to a firstembodiment of the present invention. The channel structure of FIG. 6 isidentical to the general channel structure of FIG. 3 except step 601.That is, steps 602 to 610 of FIG. 6 are equivalent to steps 301 to 309of FIG. 3, respectively. An operation in step 601 will be described. Ifa TBS size TBS_actual to be actually transmitted is smaller than theTBS_(—)2, the Node B performs repetition on the transport blocks inorder to match the TBS_actual to the TBS_(—)2 (TrBlock Repetition). Forexample, if TBS_(—)2=5 and TBS_actual=2, the Node B repeats the 2transport blocks thus to generate 5 transport blocks.

[0088] The transport block repetition operation performed in step 601 bythe transmitter will be described with reference to FIG. 7.

[0089]FIG. 7 is a flow chart illustrating an operating process of atransmitter according to a first embodiment of the present invention.Referring to FIG. 7, in step 701, a Node B determines the number ofcodes to be assigned and an MCS level, and then proceeds to step 702. Instep 702, the Node B calculates P_CAPA, TBS_(—)1 and TBS_(—)2 using thedetermined number of codes and the determined MCS level, and thenproceeds to step 703. In step 703, the Node B determines a correlationbetween the number, TBS_actual, of transport blocks to be transmitted toa corresponding UE and the calculated TBS_(—)2, and determines whetherTBS_actual is larger than TBS_(—)2. As a result of the determination, ifthe TBS_actual is smaller than or equal to the TBS 2, the Node Bproceeds to step 704. In step 704, the Node B repeats the TBS_actualtransport blocks in order to match the number, TBS_(—)2, of thetransport blocks to the number, TBS_actual, of the transport blocks, andthen ends the process. However, if the TBS_actual is larger than theTBS_(—)2 in step 703, the Node B proceeds to step 705. In step 705, theNode B performs the channel handling process described in conjunctionwith of FIG. 6, beginning at the transport block concatenation processof step 602.

[0090] So far, the first embodiment of the present invention has beendescribed with reference to FIGS. 6 and 7. Next, a method for reducing asize of the TBS field according to a second embodiment of the presentwill be described.

[0091] (2) Second Embodiment

[0092] The second embodiment of the present invention reduces a size ofthe TBS field based on the MCS level and the TBS_actual withoutperforming repetition in a transport block unit.

[0093] As described before, the P_CAPA is a function of the number ofassigned codes and the MCS level. If the number of codes is defined as1˜NC_MAX, the MCS level is defined as MCS_(—)1˜MCS_MAX, and P_CAPAcorresponding to NC_j and MCS_k is defined as P_CAPA(NC_j, MCS_k), thena range of P_CAPA(NC_j, MCS_k) becomes P_CAPA(1,MCS_(—)1)˜P_CAPA(NC_MAX,MCS_MAX), as illustrated in Equation (9).

P_CAPA(1,MCS _(—)1)=MCS_(—)1*480

P_CAPA(1,MCS _(—)2)=MCS _(—)2*480

P_CAPA(2,MCS _(—) n)=MCS _(—) n*480*2

P_CAPA(NC_MAX, MCS_MAX)=MCS_MAX*480*NC_MAX  Equation (9)

[0094] In Equation (9), if a portion corresponding to an actualtransport block in the P_CAPA is defined as P_ACAPA, the P_ACAPA can berepresented by

P_ACAPA(1,MCS _(—)1)=MCS _(—)1*480−CRC-Header_Size

P_ACAPA(1,MCS _(—)2)=MCS _(—)2*480−CRC-Header_Size

P_ACAPA(2,MCS _(—) n)=MCS _(—) n*480*2−CRC-Header_Size

P_ACAPA(NC_MAX, MCS_MAX)=MCS_MAX*480*NC_MAX−CRC-Header_Size  Equation(10)

[0095] In the second embodiment of the present invention, the Node B andthe UE determine the MCS level and the code assignment in accordancewith Rule 1 to Rule 4 below.

[0096] Rule 1

[0097] A Node B and a UE set TB_Size to P_ACAPA(1,MCS_(—)1)

[0098] Rule 2

[0099] After determining an MCS level and code assignment, a Node Bcalculates P_ACAPA according to. If the calculated P_ACAPA is largerthan the product of TB_Size and TBS_actual, Rule 3 and Rule 4 are used.If, however, the calculated P_ACAPA is smaller than the product ofTB_Size and TBS_actual, the assigned MCS level and codes are used.

[0100] Rule 3

[0101] The product of TBS_actual and TB_Size is set to P_ACAPA_target.

[0102] Rule 4

[0103] P_ACAPA most approximate to the P_ACAPA_target is determined, andan MCS level and codes are assigned according to the determined P_ACAPA.

[0104] Now, an operation of a transmitter according to a secondembodiment of the present invention will be described with reference toFIG. 8.

[0105]FIG. 8 is a flow chart illustrating an operating process of atransmitter according to a second embodiment of the present invention.Referring to FIG. 8, in step 801, a Node B determines the number ofcodes and an MCS level to be assigned to user data, and then proceeds tostep 802. In step 802, the Node B calculates P_ACAPA based on thedetermined number of codes and the determined MCS level, and thenproceeds to step 803. In step 803, the Node B determines whether thecalculated P_ACAPA is smaller than P_ACAPA_target. As a result of thedetermination, if the calculated P_ACAPA is larger than or equal toP_ACAPA_target, the Node B proceeds to step 804. In step 804, the Node Bdetermines the MCS level and the number of codes according to P_ACAPAmost approximate to the P_ACAPA_target, and then proceeds to step 805.In step 805, the Node B reassigns the MCS level and the number of codesbe assigned to the user data to the MCS level and the number of codes,determined in step 804, and then proceeds to step 806.

[0106] However, if the calculated P_ACAPA is smaller than P_ACAPA_targetin step 803, the Node B proceeds to step 806. In step 806, the Node Bperforms the channel handling process described in conjunction with ofFIG. 6, beginning at the transport block concatenation process of step602.

[0107] Hitherto, the second embodiment of the present invention has beendescribed with reference to FIG. 8. Next, a method for reducing a sizeof the TBS field according to a third embodiment of the present will bedescribed.

[0108] (3) Third Embodiment

[0109] The third embodiment of the present invention reduces a size ofthe TBS field by matching TBS information to a logical value rather thanan absolute value.

[0110] If a state in which N channelization codes are assigned to agiven UE and an MCS level M is determined is defined as S(N,M), an HSDPAcommunication system has states of S(1,1)˜S(Code_MAX, MCS_MAX). Here,Code_MAX means the total number of channelization codes assignable to ahigh-speed downlink shared channel in the HSDPA communication system,and MCS_MAX means the highest MCS level assignable by the HSDPAcommunication system.

[0111] In general, a Node B determines an MCS level based on a channelquality between the Node B and a given UE, and determines the number ofchannelization codes based on an amount of data to be transmitted to thecorresponding UE. For example, if it is assumed that a state of thegiven UE is S(X,Y), a correlation between the number, X, of codes andthe number of transport blocks to be transmitted over a high-speeddownlink shared channel is defined as

TBS_MAX_(—) WOF(X−1,Y)<TBS_variation(X,Y)<TBS_MAX(X,Y)  Equation (11)

[0112] In Equation (11), TBS_variation(X,Y) means a variation in TBSavailable in S(X,Y), and TBS_MAX(X,Y) means the maximum number of TBsthat can be transmitted in S(X,Y), and its size is determined based on apermissible maximum puncturing value for rate matching. Here, the“permissible maximum puncturing value” means the maximum number of bitsthat can be punctured for rate matching. If the permissible maximumpuncturing value is set to a high value, a transmission quality of userdata is degraded but an amount of transmittable data is increased. Inaddition, TBS_MAX(X,Y) can be expressed as

TBS_MAX(X,Y)=(P_ACAPA(X,Y)−RM_MAX_bit)/TB_Size  Equation (12)

[0113] In Equation (12), if RM_MAX_bit is restricted to a value smallerthan TB_Size, Equation (12) can be changed into Equation (13). Further,the RM_MAX_bit denotes the maximum RM value in terms of bit.

TBS_MAX(X,Y)=RU[P_ACAPA(X,Y)/TB_Size]  Equation (13)

[0114] In Equation (13), TBS_MAX_WOF(X−1,Y) means the maximum number oftransport blocks that can be transmitted in S(X−1,Y) without performingpuncturing. This can be expressed as

TBS_MAX_(—) WOF(X−1,Y)=RD[P_ACAPA(X−1,Y)/TB_Size]  Equation (14)

[0115] Finally, the TBS_variation(X,Y) is expressed as

RD[(P_CAPA(X−1,Y)−CRC-Header_Size)/TB_Size]<TBS_variation(X,Y)≦RU[(P_CAPA(X,Y)−CRC-Header_Size)/TB_Size]  Equation(15)

[0116] In Equation (15), P_CAPA(X,Y)=X*480*MCS_Y.

[0117] The values stated above will be described with reference to FIG.9.

[0118]FIG. 9 illustrates a TBS variation TBS_variation(X,Y) available ina state where X codes are assigned and an MCS level Y is assigned,according to a third embodiment of the present invention.

[0119] Referring to FIG. 9, a size of the TBS_variation(X,Y) is equal toa difference between TBS_MAX_WOF(X−1,Y) and TBS_MAX(X,Y). A Node B canreduce an amount of transmission information by transmitting only therelative difference from TBS_MAX_WOF at a corresponding timing pointinstead of transmitting an absolute TBS size before transmitting ahigh-speed downlink shared channel to a UE. For example, if TB_Size is100 bits, the number of codes is 10, an MCS level n designates {fraction(1/2)} turbo coding and 16 QAM (Quadrature Amplitude Modulation), a CRCsize is 24 bits, Header_Size is 10 bits, and an RM size converted interms of bit is 34 bits, then

P_CAPA(10,n)=480*10*1/2*4=9600 bits

P_ACAPA(10,n)=9600−24−10=9566 bits

[0120] In this state, if it is assumed that 34-bit puncturing is usedfor rate matching, then the number of TBs becomes 96. In theconventional HSDPA communication system, 96 TBs must be transmittedusing a TBS field. Thus, at least RU(log2(95)) or more bits must beassigned. However, according to the third embodiment,TBS_MAX_WOF(9,n)=RD[(P_ACAPA(X−1,Y))/TB_Size]=RD(8606/100)=86.Therefore, the Node B is allowed to simply transmit, to the UE,information on a difference, 10, between the number, 96, of actuallytransmitted TBs and TBS_MAX_WOF(9,n).

[0121] In the third embodiment of the present invention, since thenumber of bits that must be assigned to transmit a TBS size over a TFRIfield on a shared control channel should be able to cover the maximumTBS_variation value, it can be expressed as

TBS_variation_MAX=TBS_variation(Code_Max, MCS_MAX)

TBS_variation(Code_Max, MCS_MAX)=RU[P_ACAPA(Code_MAX,MCS_MAX)/TB_Size]−RD[P_CAPA(Code_MAX−1, MCS_MAX)/TB_Size]

Field_Size_(—) TBS=log2[TBS_Variation_MAX]bits  Equation (16)

[0122] In Equation (16), Field_Size_TBS means the number of bits thatmust be assigned to a TBS field.

[0123] The Node B substitutes a value of Equation (17) into a TBS fieldon a shared control channel in S(X,Y).

Value_(—) TBS=TBS_actual−TBS_MAX_(—) WOF(X−1,Y)  Equation (17)

[0124] In Equation (17), TBS_actual denotes the number of actuallytransmitted TBs, and Value_TBS means a value to be inserted into a TBSfield by the Node B, i.e., a value determined by subtracting the numberof actually transmitted TBs from the number of TBs that can be maximallytransmitted.

[0125] If the Node B transmits the Value_TBS calculated from Equation(17) to a UE over a TFRI field, the UE calculates the number of actuallytransmitted TBs based on the received Value_TBS in accordance withEquation (18).

TBS_actual=Value_(—) TBS+TBS_MAX_(—) WOF(X−1,Y)  Equation (18)

[0126] Next, a structure of a transceiver according to first to thirdembodiments of the present invention will be described with reference toFIGS. 10 and 11.

[0127]FIG. 10 is a block diagram illustrating a structure of atransmitter for an HSDPA communication system according to an embodimentof the present invention. Referring to FIG. 10, before transmitting userdata over a high-speed downlink shared channel, a Node B assigns thenumber of codes to be assigned to the user data through a code assigner1006, assigns an MCS level to be assigned to the user data through anMCS controller 1005, and provides a multiplexer (MUX) 1007 with a TBSsize, or information on the number of transport blocks to betransmitted, through a rate matching controller 1004. Here, the codeassigner 1006 assigns the number of codes taking into consideration astate of a user buffer 1001, or an amount of user data stored in theuser buffer 1001, and the rate matching controller 1004 determines thenumber of transport blocks to be transmitted, depending on an amount ofuser data stored in the user buffer 1001. The MCS controller 1005determines an MCS level taking into consideration channel qualityinformation from an uplink control information processor 1002 whichprocesses uplink control information transmitted by a corresponding UE.

[0128] The multiplexer 1007 generates a bit stream in accordance with aslot format by multiplexing information provided from the rate matchingcontroller 1004, the MCS controller 1005 and the code assigner 1006, andprovides the generated bit stream to a CRC operator 1008. The CRCoperator 1008 inserts CRC into the bit stream output from themultiplexer 1007, and provides the CRC-inserted bit stream to amultiplexer 1009. The multiplexer 1009 generates a bit stream inaccordance with the slot format of the shared control channelillustrated in FIG. 2 by multiplexing the CRC-inserted bit stream outputfrom the CRC operator 1008 with HARQ (Hybrid Automatic RetransmissionRequest) information provided from an HARQ controller (1003), andprovides its output to a spreader 1010. The spreader 1010 spreads asignal output from the multiplexer 1009 with a preset spreading code,and provides the spread signal to a scrambler 1011. The scrambler 1011scrambles the spread signal output from the spreader 1010 with a presetscrambling code, and provides the scrambled signal to a summer 1012.

[0129] The summer 1012 sums up the scrambled signal output from thescrambler 1011 and signals on the remaining channels except the sharedcontrol channel, e.g., dedicated physical channels, and provides thesummed signal to a modulator 1013. The modulator 1013 modulates thesummed signal output from the summer 1012 by preset modulation, andprovides the modulated signal to an RF (Radio Frequency) processor 1014.The RF processor 1014 up-converts the modulated signal output from themodulator 1013 into an RF signal, and transmits the RF signal through anantenna 1015.

[0130] Next, a structure of a receiver according to an embodiment of thepresent invention will be described with reference to FIG. 11.

[0131]FIG. 11 is a block diagram illustrating a structure of a receiverfor an HSDPA communication system according to an embodiment of thepresent invention. Referring to FIG. 11, an RF signal received throughan antenna 1101 is converted into a baseband signal by an RF processor1102, and then applied to a demodulator 1103. The demodulator 1103demodulates the baseband signal output from the RF processor 1102 by ademodulation technique corresponding to the modulation technique used inthe transmitter, and provides the demodulated signal to a descrambler1104. The descrambler 1104 descrambles the demodulated signal outputfrom the demodulator 1103, and provides the descrambled signal to adespreader 1105. The despreader 1105 despreads the descrambled signaloutput from the descrambler 1104, and provides the despread signal to ademultiplexer (DEMUX) 1106.

[0132] The demultiplexer 1106 demultiplexes the despread signal outputfrom the despreader 1105 into TFRI field, CRC field and HARQ field, andprovides the HARQ field to an HARQ controller 1112 and the remainingTFRI field and CRC field to a CRC operator 1107. The CRC operator 1107performs a CRC operation on a signal output from the demultiplexer 1106,and provides its output to a demultiplexer 1108. The demultiplexer 1108demultiplexes a signal output from the CRC operator 1107 into codeinformation, MCS level information and rate matching parameter, andprovides the code information to a code information reception block1109, the MCS level information to an MCS controller 1110, and the ratematching parameter to a rate matching controller 1111.

[0133] The transmitter and the receiver of FIGS. 10 and 11 according tothe present invention are identical in structure to a transmitter and areceiver for the general HSDPA communication system. However, the ratematching controller 1004 in the transmitter and the rate matchingcontroller 1111 in the receiver operate in a different way according tofirst to third embodiments.

[0134] Next, an operation of the rate matching controller 1004 in thetransmitter will be separately described with reference to theconventional method and the first to third embodiments of the presentinvention.

[0135]FIGS. 12B to 12D schematically illustrate an operation of the ratematching controller 1004 of FIG. 10. Before a description of FIGS. 12Ato 12D, it should be noted that reference numerals in FIGS. 12A to 12Dare identical to the reference numerals used in FIGS. 6 and 10. Forexample, reference numeral 1001 of FIG. 12A indicates that TBS isprovided from the user buffer 1001.

[0136] Specifically, FIG. 12A illustrates a conceptual operation of arate matching controller in a transmitter for a conventional HSDPAcommunication system. The rate matching controller receives TBS, or thenumber of transport blocks for user data stored in user buffer, andprovides the intact TBS value to amultiplexer.

[0137]FIG. 12B illustrates a conceptual operation of the rate matchingcontroller 1004 according to a first embodiment of the presentinvention. The rate matching controller 1004 receives TBS, or the numberof transport blocks for the user data stored in the user buffer 1001,receives an MCS level from the MCS controller 1005 and receives thenumber of assigned codes from the code assigner 1006. Then, the ratematching controller 1004 calculates P_CAPA, TBS_(—)1 and TBS_(—)2 bysubstituting the received TBS for TBS_actual and using the MCS level andthe number of codes. If TBS_actual is smaller than TBS_(—)2, the ratematching controller 1004 performs repetition on the transport blocksuntil TBS_actual becomes equal to TBS_(—)2 (Step 601 of FIG. 6). Afterthe repetition, if TBS_actual is equal to TBS_(—)2, the rate matchingcontroller 1004 provides the multiplexer 1007 with 1-bit informationindicating that an actual transport block set for the user dataunderwent repetition. However, if TBS_actual is equal to TBS_(—)1, therate matching controller 1004 provides the multiplexer 1007 with 1-bitinformation indicating that an actual transport block set for the userdata underwent puncturing.

[0138]FIG. 12C illustrates a conceptual operation of the rate matchingcontroller 1004 according to a second embodiment of the presentinvention. The rate matching controller 1004 receives TBS, or the numberof transport blocks for the user data stored in the user buffer 1001,receives an MCS level from the MCS controller 1005 and receives thenumber of assigned codes from the code assigner 1006. Then, the ratematching controller 1004 calculates P_ACAPA_target by substituting thereceived TBS for TBS_actual, and calculates P_ACAPA based on the MCSlevel and the number of codes. If P_ACAPA_target is larger than P_ACAPA,the rate matching controller 1004 provides the multiplexer 1007 with1-bit information indicating puncturing. If, however, P_ACAPA_target issmaller than P_ACAPA, the rate matching controller 1004 provides themultiplexer 1007 with 1-bit information indicating repetition.

[0139]FIG. 12D illustrates a conceptual operation of the rate matchingcontroller 1004 according to a third embodiment of the presentinvention. The rate matching controller 1004 receives TBS, or the numberof transport blocks for the user data stored in the user buffer 1001,receives an MCS level from the MCS controller 1005 and receives thenumber of assigned codes from the code assigner 1006. Then, the ratematching controller 1004 calculates TBS_MAX_WOF(X−1,Y) by substitutingthe received TBS for TBS_actual and using the MCS level and the numberof codes. Here, X denotes the number of codes and Y denotes the MCSlevel. The rate matching controller 1004 calculates a TBS differencevalue Value_TBS to be provided to the multiplexer 1007 based on thecalculated TBS_MAX_WOF(X−1,Y) in accordance with the following formula.

Value_(—) TBS=TBS_actual−TBS_MAX_(—) WOF(X−1,Y)

[0140] Next, an operation of the rate matching controller 1111 in thereceiver will be separately described with reference to the conventionalmethod and the first to third embodiments of the present invention.

[0141]FIGS. 13B to 13D schematically illustrate an operation of the ratematching controller 1111 of FIG. 11. Before a description of FIGS. 13Ato 13D, it should be noted that reference numerals in FIGS. 13A to 13Dare identical to the reference numerals used in FIG. 11. For example,reference numeral 1108 of FIG. 13A indicates that TBS is provided fromthe demultiplexer 1008.

[0142] Specifically, FIG. 13A illustrates a conceptual operation of arate matching controller in a receiver for a conventional HSDPAcommunication system. The rate matching controller calculates a ratematching value RM based on the received TBS value, and provides thecalculated rate matching value to a rate de-matcher (not shown) of thereceiver thus to correct the rate matched portion. Here, the ratematching value RM is calculated by

RM=P_ACAPA−TBS*TB_Size

[0143]FIG. 13B illustrates a conceptual operation of the rate matchingcontroller 1111 according to a first embodiment of the presentinvention. The rate matching controller 1111 calculates the ratematching value RM based on the values provided from the demultiplexer1008, and provides the calculated rate matching value RM to the ratede-matcher thus to correct the rate matched portion. Here, the ratematching value RM according to the first embodiment of the presentinvention is calculated by

RM=P_ACAPA−TBS _(—)1*TB_Size if repetition

RM=P_ACAPA−TBS _(—)2*TB_Size if puncturing

TBS _(—)1=RU(TBS_estimated), TBS _(—)2=RD(TBS_estimated)

TBS_estimated=P_ACAPA/TB_Size

[0144]FIG. 13C illustrates a conceptual operation of the rate matchingcontroller 1111 according to a second embodiment of the presentinvention. The rate matching controller 1111 calculates the ratematching value RM based on the values provided from the demultiplexer1008, and provides the calculated rate matching value RM to the ratede-matcher thus to correct the rate matched portion. Here, the ratematching value RM according to the second embodiment of the presentinvention is calculated by

RM=P_ACAPA−TBS_(—)1*TB_Size if repetition

RM=P_ACAPA−TBS _(—)2*TB_Size if puncturing

TBS _(—)1=RU(TBS_estimated), TBS _(—)2=RD(TBS_estimated)

TBS_estimated=P_ACAPA/TB_Size

[0145]FIG. 13D illustrates a conceptual operation of the rate matchingcontroller 1111 according to a third embodiment of the presentinvention. The rate matching controller 1111 calculates the ratematching value RM based on the values provided from the demultiplexer1008, and provides the calculated rate matching value RM to the ratede-matcher thus to correct the rate matched portion. The rate matchingvalue RM according to the third embodiment of the present invention iscalculated by

RM=P_ACAPA−TBS_actual*TB_Size

TBS_actual=Value_(—) TBS+TBS_MAX_(—) WOF(X−1,Y)

[0146] As described above, the present invention reduces a size of afield used to transmit control information over a shared controlchannel, especially such control information as TBS size information inan HSDPA communication system according to the present invention,thereby increasing efficiency of downlink channel resources. Further, inthe HSDPA communication system, the present invention transmits TBS sizeinformation to a UE over a shared control channel with a single bit,thereby increasing transmission efficiency of TBS size information.

[0147] While the invention has been shown and described with referenceto a certain preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

What is claimed is:
 1. A method for transmitting TBS (Transport BlockSet) information to a UE (User Equipment) in a high-speed packetcommunication system, comprising the steps of: determining at least oneModulation order among a plurality of modulation orders and at least onecode among a plurality of codes; determining the number of radio framedata bits based on the determined modulation order and the number of thedetermined codes; comparing the number of coded bits for a user datawith the number of radio frame data bits; setting a flag indicating arepetition if the number of coded bits for a user data is less than thenumber of radio frame data bits; setting a flag indicating a puncturingif the number of coded bits for a user data is greater than the numberof radio frame data bits; and transmitting the TBS information includingthe flag.
 2. The method of claim 1, wherein the interval is equal to atransport block unit.
 3. A method for transmitting TBS (Transport BlockSet) information to a UE (User Equipment), comprising the steps of:determining a first number of coded bits based on a minimum modulationorder and one code; determining at least one modulation order among aplurality of modulation orders and at least one code among a pluralityof codes; determining a second number of coded bits based on thedetermined modulation order and the number of the determined codes; andcomparing a second number of coded bits with a product of the firstnumber of coded bits; and re-determining an modulation order having thenumber of radio frame data bits and the number of codes by thecomparing, both numbers being most approximate to the product of thefirst number of coded bits.
 4. The method of claim 3, wherein the numberof transport blocks constituting the TBS is determined using the firstnumber of information bits.
 5. A method for transmitting TBS (TransportBlock Set) information to a UE (User Equipment), comprising the stepsof: determining at least one modulation order among a plurality ofmodulation orders and at least one code among a plurality of codes;determining a first number of information bits that can be transmittedwith the determined modulation order and the number of the determinedcodes; determining a second number of information bits that can betransmitted with the determined modulation order and the number of thedetermined codes minus one; and determining a third number of transportblocks that can be transmitted with the first number of informationbits, determining a fourth number of transport blocks that can betransmitted with the second number of information bits, and thentransmitting a difference between the third number of transport blocksand the fourth number of transport blocks.
 6. The method of claim 5,wherein the third number of transport blocks is equal to a valuedetermined by rounding down a value determined by dividing the firstnumber of information bits by a given number of bits constituting thetransport block.
 7. A method for receiving TBS (Transport Block Set)information in a high-speed packet communication system in which a NodeB separates transmission information bits into a plurality of transportblocks each having a first number of bits, transmits a TBS including astream of the transport blocks and transmits information on the TBS to aUE (User Equipment) without transmitting TBS size information indicatingthe number of the transport blocks, comprising the steps of: receivingover a downlink shared channel an modulation order assigned to the TBS,the number of codes assigned to the TBS, and a repetition/puncturingflag indicating whether the TBS underwent repetition or puncturing;determining a second number of information bits that can be transmittedwith the assigned modulation order and the number of the assigned codes;calculating a third number of transport blocks by rounding up a valueddetermined by dividing the second number of information bits by thefirst number of bits, and calculating a fourth number of transportblocks by rounding down a value determined by dividing the second numberof information bits by the first number of bits; if the receivedrepetition/puncturing flag indicates that the TBS underwent repetition,determining the size of the TBS as the third number of transport blocks,and determining a rate matching value by subtracting a product of thethird number of transport blocks and the first number of bits from thesecond number of information bits; and if the receivedrepetition/puncturing flag indicates that the TBS underwent puncturing,determining the size of the TBS as the fourth number of transportblocks, and determining a rate matching value by subtracting a productof the fourth number of transport blocks and the first number of bitsfrom the second number of information bits.
 8. A method for receivingTBS (Transport Block Set) information in a high-speed packetcommunication system in which a Node B separates transmissioninformation bits into a plurality of transport blocks each having afirst number of bits, transmits a TBS including a stream of thetransport blocks and transmits the TBS information to a UE (UserEquipment) without transmitting a TBS size information indicating thenumber of the transport blocks, comprising the steps of: receiving overa downlink shared channel an modulation order assigned to the TBS, thenumber of codes assigned to the TBS, a second number of transport blocksthat can be transmitted with the assigned modulation order and thenumber of the assigned codes, and a third number of transport blocksthat can be transmitted with the assigned modulation order and thenumber of the assigned codes minus one; determining a fourth number ofinformation bits that can be transmitted with the assigned modulationorder and the number of the assigned codes; and determining a ratematching value by subtracting a fifth number determined by adding thedifference to the third number of transport blocks and a sixth numberdetermined by multiplying the fifth number by the first number of bits,from the fourth number of information bits.
 9. The method of claim 8,wherein the fourth number of transport blocks is equal to a valuedetermined by rounding up a value determined by dividing the secondnumber of information bits by a given number of bits constituting thetransport block.
 10. An apparatus for transmitting TBS (Transport BlockSet) information to a UE (User Equipment) without transmitting TBS sizeinformation indicating the number of transport blocks in a high-speedpacket communication system which separates transmission informationbits into a plurality of transport blocks each having a given number ofbits and transmits a TBS including a stream of the transport blocks,comprising: an MCS (Modulation and Coding Scheme) level controller forassigning one MCS level among a plurality of MCS levels according tochannel quality information received from the UE; a code assigner forassigning at least one code among a plurality of codes according to thenumber of the transmission information bits; a rate matching controllerfor determining the number of transmittable information bits based onthe determined MCS level and the number of the determined codes; and atransmitter for transmitting the assigned MCS level, the number of theassigned codes, and the repetition flag or the puncturing flag, over adownlink, wherein if the number of coded bits for the transmissioninformation bits is less than the number of transmittable informationbits, repeating some of the coded bits at regular intervals andassigning a repetition flag indicting the repetition, and if the numberof coded bits is greater than or equal to the number of transmittableinformation bits, puncturing some of the coded bits at regular intervalsand assigning a puncturing flag indicting the puncturing.
 11. Theapparatus of claim 10, wherein the interval is equal to a transportblock unit.
 12. The method of claim 10, wherein the second number oftransport blocks is equal to a value determined by rounding up a valuedetermined by dividing the fourth number of information bits by thefirst number of bits.
 13. The method of claim 10, wherein the thirdnumber of transport blocks is equal to a value determined by roundingdown a valued determined by dividing a seventh number of informationbits that can be transmitted with the assigned MCS level and the numberof the assigned codes minus one, by the first number of bits.
 14. Anapparatus for receiving TBS (Transport Block Set) information in ahigh-speed packet communication system, in which a Node B separatestransmission information bits into a plurality of transport blocks eachhaving a first number of bits, transmits a TBS including a stream of thetransport blocks and transmits the TBS information to a UE (UserEquipment) without transmitting TBS size information indicating thenumber of transport blocks, comprising: a receiver for receiving adownlink shared channel signal, and detecting from the downlink sharedchannel signal an MCS (Modulation and Coding Scheme) level assigned tothe TBS, the number of codes assigned to the TBS, and arepetition/puncturing flag indicating whether the TBS underwentrepetition or puncturing; and a rate matching controller for determininga second number of information bits that can be transmitted with theassigned MCS level and the number of the assigned codes, calculating athird number of transport blocks by rounding up a value determined bydividing the second number of information bits by the first number ofbits, calculating a fourth number of transport blocks by rounding down avalue determined by dividing the second number of information bits bythe first number of bits, wherein if the received repetition/puncturingflag indicates that the TBS underwent repetition, determining a size ofthe TBS as the third number of transport blocks and determining a ratematching value by subtracting a product of the third number of transportblocks and the first number of bits from the second number ofinformation bits, and if the received repetition/puncturing flagindicates that the TBS underwent puncturing, determining the size of theTBS as the fourth number of transport blocks and determining a ratematching value by subtracting a product of the fourth number oftransport blocks and the first number of bits from the second number ofinformation bits.
 15. An apparatus for receiving TBS (Transport BlockSet) information in a high-speed packet communication system, in which aNode B separates transmission information bits into a plurality oftransport blocks each having a first number of bits, transmits aTBSincluding a stream of the transport blocks and transmitsTBSinformation to a UE (User Equipment) without transmitting TBS sizeinformation indicating the number of transport blocks, comprising: areceiver for receiving a downlink shared channel signal, and detectingfrom the downlink shared channel signal an MCS (Modulation and CodingScheme) level assigned to the TBS, the number of codes assigned to theTBS, and a difference between a second number of transport blocks thatcan be transmitted with the assigned MCS level and the number of theassigned codes and a third number of transport blocks that can betransmitted with the assigned MCS level and the number of the assignedcodes minus one; and a rate matching controller for determining a fourthnumber of information bits that can be transmitted with the assigned MCSlevel and the number of the assigned codes, and determining a ratematching value by subtracting a fifth number determined by adding thedifference to the third number of transport blocks and a sixth numberdetermined by multiplying the fifth number by the first number of bits,from the fourth number of information bits.
 16. The apparatus of claim15, wherein the second number of transport blocks is equal to a valuedetermined by rounding up a value determined by dividing the fourthnumber of information bits by the first number of bits.
 17. Theapparatus of claim 15, wherein the third number of transport blocks isequal to a value determined by rounding down a valued determined bydividing a seventh number of information bits that can be transmittedwith the assigned MCS level and the number of the assigned codes minusone, by the first number of bits.